A variety of techniques are used to treat blood clots in patients. Infusion is commonly used to deliver a thrombolytic agent into a blood vessel in a patient, such as a vein, for dissolving the material of the blood clot or thrombus. Other techniques utilize mechanical action of a percutaneously introduced tool to break up thrombus material, for removal from the patient. Specially designed catheters with augers or various other cutting implements, sometimes used in combination with thrombolytics, are well known and widely used.
Rheolytic thrombectomy is yet another technique used to treat blood clots, and exploits the creation of a vacuum by high velocity fluid injected into and withdrawn from a body lumen in a patient to both disrupt a thrombus and draw its fragments out of the vessel. Increased fluid velocity near ports in a rheolytic catheter leads to reduced pressure creating the vacuum according to well known fluid dynamic principles. One standard design for a rheolytic thrombectomy catheter is sold under the trade name Angiojet®. Another rheolytic thrombectomy catheter is known from U.S. Pat. No. 8,439,878 B2 to Bonnette et al. The catheter in Bonnette et al. has a self-inflating balloon with drug infusion capabilities, where the self-inflation apparently occurs in response to flow of fluid from a fluid jet emanator to inflow orifices located distal to the balloon. While these and other rheolytic thrombectomy catheters are in widespread use, there is always room for improvement.